A High Altitude Simulation Test or HAST (sometimes referred to as a Hypoxic Challenge Test or fitness to fly assessment) is a safe procedure in which clinicians can determine how well your child’s body will adapt to the change in conditions while travelling in an aircraft and whether any interventions are required.
During commercial flights, an aircraft can reach an altitude of up to 30,000 feet where the air cabin gets pressurized to a range between 5000 – 8000 feet. As a result of these changes in pressure and altitude, oxygen levels in an aircraft falls lower than at sea-level (from 21% oxygen in room air to 13-15% in commercial aircrafts or high altitudes), therefore oxygen levels in the blood will also decrease slightly. In healthy individuals, the body will usually compensate to overcome these changes, however, in some individuals with known respiratory and cardiovascular conditions, this can sometimes cause complications during travel. In order to ensure that it is safe for your child to fly, we carry out an assessment that simulates the conditions inside an aircraft to determine if they are “fit to fly” and whether or not they will require supplemental oxygen during a flight.